The present invention relates to a liquid synfuel additive composition for application to materials such as coal for facilitating more complete and efficient combustion thereof.
There is no existing prior art so far as the inventors hereof are aware. There have been fatty acids used in making wax emulsions for the purpose of sealing them against liquid water.
Although polyvinyl alcohol is know both as a film-forming agent and an emulsifier, it does not meet ASTM standard C 309-95 when tested as a liquid membrane-forming compound for curing concrete. The reason for this is that although polyvinyl alcohol typically exhibits a low permeability to gases, it does not exhibit a low permeability to either ammonia or water vapor. As a result, polyvinyl alcohol is insufficient to prevent significant loss of water from concrete during curing.
Paraffinic compounds are known to be water repellant and thus paraffin is typically used as a compound of wood preservative agents. For Example, U.S. Pat. No. 4,389,446 discloses a composition useful as a wood preservative agent which includes an organic solvent, solid paraffin as a water repellant agent and a biocide.
There is a great need for additives to combustibles these days which tend to act as chemical change agents to facilitate more complete combustion. Accordingly, there is an ongoing need for such chemical change agents to facilitate more complete combustion of coal.
It is an object of this invention to provide a chemical change agent to facilitate the complete combustion of coal, and
It is another object of this invention to provide a synfuel additive which is environmentally acceptable and inexpensive, and
These and other objects of this invention will become more apparent when reference is had to the accompanying specification
The present invention relates to an aqueous composition to be used as a synfuel additive for combustible materials, especially coal.
The product contemplated by this invention is a latex emulsion comprising a paraffin wax or wax, a polyvinyl alcohol and water. The percentage of each ingredient is as follows:
Other additives can be used to improve properties including varying percentages of polyvinyl acetate. A blend of 90% of the latex emulsion, specified above, with 10% polyvinyl acetate produced good burning results. Likewise, the latex emulsion by itself proved to be a satisfactory synfuel additive. The use of the polyvinyl alcohol, makes the emulsion.
The use of the polyvinyl agent produces a chemical change agent which turns the composition into a synfuel. The invention contemplates adding polyvinyl acetate to the composition to enhance it""s combustibility. It is contemplated that 10% or more may be added to the composition. The range can be from 0 to 20%.
It is also contemplated to add a pigment composition to make the chemical change agent black so as to blend with the coal. The additive may interfere with the strength of the film.
The exact percentages of the ingredients apparently can vary as follows:
Further testing is required to determine if the polyvinyl alcohol will work by itself. The Paraffin wax will not qualify as a synthetic material unless it is a synthetic wax.
The combination of polyvinyl alcohol and wax is synthetic since the polyvinyl alcohol is synthetic and is required to emulsify the wax.
The best product will have a solids content of from 25% to 50% with a 2% to 10% of the solids coming from polyvinyl alcohol and the remainder coming from the wax. The polyvinyl acetate may be added as needed.
The action of the moisture barrier and vapor barrier aspects of the composition are thought to be important to the action of the synfuel.
The compositions of the invention generally comprise at least one hydrocarbon was dispersed in an aqueous emulsion, which can form a film on particles of coal. The emulsions used in the composition of the present invention are preferably made using polyvinyl alcohol as the emulsifying agent. Thus, in it broadest form, the present invention relates to an aqueous composition comprising a hydrocarbon wax, a polyvinyl alcohol emulsifying agent, and the balance of water.
The aqueous composition of the present invention is designed for use as a coating for application to materials when burned. The purpose of using the film of the present invention is aide the combustion of the material to which it is applied.
Typical materials to which the composition of the present invention may be applied include materials such as coal, both bituminous and sub bituminous as well as lignite, wood and rubber.
The aqueous film composition of the present invention may be applied to a number of different materials. Both whole coal as well as coal xe2x80x9ctailingsxe2x80x9d or fines can be coated with the instant film to facilitate combustion of the resulting material as a synfuel.
Representative non-limiting examples of the hydrocarbon waxes of the present invention include paraffin wax, slack wax, microcrystalline wax, olefin waxes and other, conventional, know hydrocarbon waxes. More preferred hydrocarbon waxes are those made up of relatively high molecular weight components since such waxes tend to exhibit better film-forming properties.
The aqueous composition of the present invention comprises 5.0% to 45.0% by weight, based on the total weight of the composition, of the hydrocarbon wax. More preferably, the aqueous composition of the present invention comprises 10% to 35% by weight of the hydrocarbon wax and, as a preferred ratio, the aqueous coating composition of the invention comprises 15 to 25% by weight of the hydrocarbon wax. Naturally, the mixtures of one or more hydrocarbon waxes may also be employed in the aqueous composition.
In addition to water and the hydrocarbon wax, the aqueous coating composition of the present invention comprises an emulsifying agent such as that the aqueous composition forms an emulsion in water, which can be applied to a coal material. The emulsifying agents useful in the present invention are the polyvinyl alcohols. Any form of polyvinyl alcohol may be employed in the present invention irrespective of its degree of hydrolysis and/or degree of polymerization. However, the degree of polymerization and degree of hydrolysis of the polyvinyl alcohol may have an impact on the strength of the film, which is formed from the aqueous coating composition of the present invention. The specific polyvinyl alcohol which is selected to be used in the present invention will be that which demonstrates the best properties in terms of combustion.
The polyvinyl alcohol emulsifying agent is employed in an amount of 1.0% to 10.0% by weight, based on the total weight of the aqueous coating composition. More preferably, the polyvinyl emulsifier comprises 2 to 5% by weight of the composition Naturally, mixtures of two or more polyvinyl alcohols having differing degrees of hydrolysis and/or polymerization may be employed in the aqueous synfuel composition of the present invention.
The composition of the present invention may also optionally include up to 1.0% by weight of a biocide, based on the total weight of the composition. Such biocides are known in the art and include pesticides and other materials designed to prevent the growth of organisms in the aqueous coating composition during storage and use. The biocide will typically be employed in an amount sufficient to prevent the growth of living organisms in the aqueous coating composition during storage. Such amounts do not usually exceed 1.0% by weight and, more preferably, only up to 0.5% by weight of the biocide is employed. Most preferably, the biocide comprises up to 0.105 by weight of the aqueous synfuel composition.
In addition, the synfuel composition of the invention may optionally contain one or more filler materials. Any conventional filler material may be used for this purpose such as oxygen containing compounds like sugar, acedic acid and salts of acedic acid and other oxygen containing compounds may be added to improve combustion.
The synfuel composition of the invention may be made by mixing the ingredients using a conventional mixing apparatus. If a prolonged storage period is anticipated, it is preferred to run the composition through a homogenizer before putting it in a storage container. The composition is storage stable for prolonged periods of six months or more. The addition of a biocide prevents the growth of undesirable organisms.
The synfuels composition of the present invention can be applied in any conventional manner. For example, the composition my be applied using spray guns immersion, etc.
The instant invention also meets all the Federal Air Quality Regulations in 40 C. F. R. This is very significant since conventional, commercially available synfuels, do not, in a lot of cases, meet the Federal Standards, as they contain hazardous components and/or volatile organic compounds. Hence, the instant invention is environmentally friendly. The addition of polyvinyl acetate to the basic composition enhances it burning ability when used with coal.